v3.5.0.2
Document and Entity Information - shares
6 Months Ended
Sep. 30, 2016
Oct. 28, 2016
Document and Entity Information [Abstract]    
Entity Registrant Name ORION ENERGY SYSTEMS, INC.  
Entity Central Index Key 0001409375  
Document Type 10-Q  
Document Period End Date Sep. 30, 2016  
Amendment Flag false  
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q2  
Current Fiscal Year End Date --03-31  
Entity Filer Category Smaller Reporting Company  
Entity Common Stock, Shares Outstanding   28,252,123